Médecins Sans Frontières’ rescue crews assist in a rescue operation after a boat capsized on Wednesday 5 August assist in

About 200 migrants are still unaccounted after a boat thought to be carrying up to 600 passengers capsized 15 miles off the coast of Libya.

Rescue crews were able to save 373 people after the disaster on Wednesday, according to the latest assessment by the Italian coastguard, while 25 were confirmed dead.

The search for survivors continued throughout the night, with five vessels patrolling the area of the disaster for signs of life, but none were found, according to Migrant Report, which is closely following the situation. Most of the passengers were believed to be from Syria, though their nationalities have not yet been confirmed.

We believe the boat was carrying about 600 people, but we will never really know how many sank

UNHCR spokesman

Six people were airlifted to the Italian island of Lampedusa for emergency medical treatment, a spokesman for UNHCR, the UN’s relief agency, said. These included a 19-month-old Palestinian girl with a high fever, whose condition has since improved. She was being treated in a hospital accompanied by three family members. The other two men – one of whom had a broken leg – were from Bangladesh.

If the death toll continues to rise, as is expected, the capsizing will be the deadliest involving migrants trying to cross the Mediterranean since April, when more than 800 died after their boat sank.

It is thought that up to 600 migrants were on board, with many believed to have been riding in the hull. These people would have had almost no chance to escape, experts said.

The boat is believed to have hit rough weather 15 miles off the Libyan coast, and made a distress call that was received by Italian naval officials.

An Irish rescue vessel, LÉ Niamh, and Dignity I, a boat operated by Médecins Sans Frontières, the international medical aid charity, were dispatched to the area. They were later joined by three other ships and a helicopter.

The boat is believed to have capsized at 1pm after it was approached by two smaller vessels operated by LÉ Niamh. Passengers are believed to have rushed to one side of the boat, which then overturned.

Migrant Report noted on Thursday that the Italian coastguard vessel, Mimbelli, then sent a helicopter to drop life rafts at the site, a quick response that saved hundreds of lives.

Save the Children said survivors were expected to land in Palermo, Sicily, late on Thursday afternoon. The aid group, which focuses on helping children and families, said it was expecting about a dozen children and a dozen women to be among the survivors, but those figures were not confirmed.

The migrants are likely to be assessed and interviewed before heading into a reception centre. Those who wish to seek asylum in Italy will be fingerprinted, but those who wish to travel to other destinations in northern Europe are unlikely to be fingerprinted by Italian authorities.

MSF said the latest tragedy highlighted the “severe lack of resources” available for rescue operations. It said its vessel received a call from Rome’s Maritime Rescue Coordination Centre at 9am, but rescued 94 other people en route. That rescue operation was complete at 12.30pm. As they approached the troubled vessel, which they said was wooden, not metal as was previously reported, the crew realised the boat had already capsized.

“It was a horrific sight, people desperately clinging to lifebelts, boats and anything they could to fight for their lives, amidst people drowning, and those who had already died,” said Juan Matías, MSF project coordinator on the Dignity I. “The fact that we were first called to assist this boat and then shortly afterwards sent to another one highlights the severe lack of resources available for rescue operations.”

The group said it began tending to the victims, five of whom were in such bad medical shape that they required evacuation by helicopter.

Young child among migrants rescued from capsized boat carrying 600 people – video

The UN refugee agency UNHCR said there was not likely to be any more information until survivors are interviewed by aid workers and Italian officials on Thursday. “We believe the boat was carrying about 600 people, but we will never really know how many sank,” said a UNHCR spokesman.

The migrant emergency is not Italy’s. It is Europe’s | Matteo Renzi

Read more

In April, a boat carrying an estimated 800 migrants overturned, also off Libya’s coast, where smugglers operate. Only 28 survivors, including two alleged smugglers, were found.

More than 2,000 people have died trying to cross the Mediterranean to Europe this year, according to the International Organization for Migration.

The aid group said the central Mediterranean route from Africa to southern Italy was far more dangerous than other routes used by migrants. It noted that, while Italy and Greece had experienced a similar inflow of migrants this year (97,000 in Italy and 90,500 in Greece), almost 2,000 had died making their way to Italy, while 60 were known to have died trying to get to Greece.

Non-governmental organisations often join migrant sea rescue operations, which are coordinated by Italy’s coastguard and are now under the umbrella of an EU taskforce known as Triton.

Last October, the EU opted not to replace the Italian-run search-and-rescue operation Mare Nostrum, which saved about 100,000 lives last year, amid fears that it was encouraging smugglers and migrants to organise more trips to Europe.